Federal inspectors since 1990 have detected violations of security procedures an average of every third day at the two Northern Virginia airports that serve metropolitan Washington.Federal Aviation Administration (FAA) records showed that the agency logged 1,236 separate security lapses between 1990 and 2000 at Washington Dulles International and Ronald Reagan Washington National airports. The airlines, though, paid fines for violations only occasionally.Only 337 violations, or 27 percent, resulted in fines, totaling $1.1 million. In reality, airlines typically are able to negotiate a much lower fine than the one levied by the FAA. Airlines that object to the penalties can take the agency to court.A total of 635 violations were handled administratively, with violators usually receiving a warning letter. Other violations went unpunished.The violations can range from mundane matters, such as record keeping or leaving a fire door open, to more serious issues, such as loaded weapons slipping past security guards.The airlines generally are responsible for baggage handling and other security issues at airports. The Sept. 11 terrorist attacks have led some to question the system. Many airline executives and lawmakers are calling for the federal government to take over security.Mary Schiavo, a former inspector general for the Department of Transportation and a longtime FAA critic, said the inspections by FAA officials and other surveillance agents rarely would result in changes."Even when they did find violations, the FAA did not get very excited about it," said Mrs. Schiavo, an aviation disaster lawyer. "They sort of went through the motions. When it came to hitting the airlines hard, they didn't do it."Mrs. Schiavo said sentiment at FAA was that if the airlines had to pay hefty fines, less money would be available to spend on security.Both Reagan and Dulles airports are run by the Metropolitan Washington Airports Authority, but each handles security differently. At Dulles, the airlines contract with one firm, Argenbright Security. At Reagan Airport, which has three terminals, the airlines have hired three different security firms, said airport spokeswoman Tara Hamilton.The FAA data show more enforcement actions at Reagan Airport (732) than at Dulles (501) over the past 10 years, but it's not clear why. It could be a result of greater scrutiny applied to Reagan Airport, which is closer to the city and has been deemed a greater security risk because of its proximity to the White House, Pentagon and other government agencies.The most common violation was a failure to detect unauthorized items at X-ray machines. Several dozen violations involved weapons of some sort.A congressional audit last year found that security screeners failed to detect 20 percent of the dangerous items hidden in baggage by inspectors.The violations at Dulles and Reagan airports were similar to those reported at the nation's other airports.FAA spokesman Roland Herwig declined to comment in detail on the violations, but said the number demonstrated a concerted effort by inspectors to scrutinize security."We test the system vigorously," he said.The airports play a minimal role in security, Miss Hamilton said. Nevertheless, the FAA took 119 enforcement actions against the airports authority or the airports themselves, and levied $56,750 in fines since 1990.In many cases, Miss Hamilton said, an FAA inspector would write up a violation for something like a fire door left open or an airport police officer not checking the badge of a familiar face entering a secure area."When you consider that these violations occurred over 10 years and that 15 to 20 million passengers a year use each airport, it places them into context," she said.